Methods and apparatus for employing different capabilities for different duplexing modes

ABSTRACT

Certain aspects of the present disclosure propose techniques for independently signaling features supported by a user equipment (UE) in different duplexing modes. The UE may be capable of communicating in frequency division duplexing (FDD) and time division duplexing (TDD) modes. The UE may obtain a FDD-specific feature group indicators (FGIs) set and a TDD-specific FGIs set, and signal at least one of the FDD-specific FGIs set or TDD-specific FGIs set. In addition, the UE may take one or more actions to reduce the likelihood of transitioning to a mode of operation that is different from its current mode of operation.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

This application is a U.S. divisional application of U.S. patentapplication Ser. No. 13/406,344, entitled “METHODS AND APPARATUS FOREMPLOYING DIFFERENT CAPABILITIES FOR DIFFERENT DUPLEXING MODES” andfiled Feb. 27, 2012, which claims priority to U.S. ProvisionalApplication No. 61/447,624, entitled, “Mechanism to Decouple FeatureSupport Between Different Duplexing Modes,” filed Feb. 28, 2011, andU.S. Provisional Application No. 61/450,995, entitled, “Mechanism toDecouple Feature Support Between Different Duplexing Modes,” filed Mar.9, 2011, both assigned to the assignee hereof, which are herebyexpressly incorporated by reference herein.

TECHNICAL FIELD

Certain aspects of the present disclosure generally relate to wirelesscommunications and, more particularly, to systems and methods that mayemploy different duplexing modes (e.g., time division duplex (TDD) andfrequency division duplex (FDD)).

BACKGROUND

Wireless communication systems are widely deployed to provide varioustypes of communication; for instance, voice and/or data can be providedvia such wireless communication systems. A typical wirelesscommunication system, or network, can provide multiple users access toone or more shared resources (e.g., bandwidth, transmit power, etc.).For instance, a system can use a variety of multiple access techniquessuch as Frequency Division Multiplexing (FDM), Time DivisionMultiplexing (TDM), Code Division Multiplexing (CDM), OrthogonalFrequency Division Multiplexing (OFDM), and others.

Generally, wireless multiple-access communication systems cansimultaneously support communication for multiple mobile devices. Eachmobile device can communicate with one or more base stations viatransmissions on forward and reverse links. The forward link (ordownlink) refers to the communication link from base stations to mobiledevices, and the reverse link (or uplink) refers to the communicationlink from mobile devices to base stations.

Current 3^(rd) generation partnership project (3GPP) specifications maydefine a set of feature group indicators (FGIs), which are signaled bythe user equipment (UE) to the network to indicate support ornon-support for certain LTE and Inter-Radio Access Technology (I-RAT)features. Examples of such features may include support for handover,measurements on another RAT, and various other features. Based on thesignaled FGIs from the UE, the network may not initiate certainprocedures towards the UE, since these will not be supported in the UE.

SUMMARY

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Themethod generally includes obtaining a FDD-specific feature groupindicators (FGIs) set and a TDD-specific FGIs set, and signaling atleast one of the FDD-specific FGIs set or TDD-specific FGIs set.

Certain aspects of the present disclosure provide a method for wirelesscommunications with a user equipment capable of communicating infrequency division duplexing (FDD) and time division duplexing (TDD)modes. The method generally includes receiving signaling of at least oneof a FDD-specific feature group indicators (FGIs) set or a TDD-specificFGIs set, and determining features supported by the UE in at least oneof a FDD mode or TDD mode, based on the received signaling.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Themethod generally includes obtaining a FDD-specific feature groupindicators (FGIs) set and TDD-specific FGIs set, signaling the FGIs setfor a current mode of operation by the UE, and taking at least oneaction designed to reduce likelihood of transitioning to a mode ofoperation that is different from the current mode of operation.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Themethod generally includes obtaining FDD-specific capabilities andTDD-specific capabilities, and sending a request to a base station toperform detach and re-attach procedures when changing from a first modeof operation to a second mode of operation, wherein the capabilitiescorresponding to the second mode of operation are transmitted to thebase station during the re-attach procedure.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes means for obtaining a FDD-specific feature groupindicators (FGIs) set and a TDD-specific FGIs set, and means forsignaling at least one of the FDD-specific FGIs set or TDD-specific FGIsset.

Certain aspects of the present disclosure provide an apparatus forwireless communications with a user equipment capable of communicatingin frequency division duplexing (FDD) and time division duplexing (TDD)modes. The apparatus generally includes means for receiving signaling ofat least one of a FDD-specific feature group indicators (FGIs) set or aTDD-specific FGIs set, and means for determining features supported bythe UE in at least one of a FDD mode or TDD mode, based on the receivedsignaling.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes means for obtaining a FDD-specific feature groupindicators (FGIs) set and TDD-specific FGIs set, means for signaling theFGIs set for a current mode of operation by the apparatus, and means fortaking at least one action designed to reduce likelihood oftransitioning to a mode of operation that is different from the currentmode of operation.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes means for obtaining FDD-specific capabilities andTDD-specific capabilities, and means for sending a request to a basestation to perform detach and re-attach procedures when changing from afirst mode of operation to a second mode of operation, wherein thecapabilities corresponding to the second mode of operation istransmitted to the base station during the re-attach procedure.

Certain aspects provide a computer-program product for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Thecomputer-program product typically includes a computer-readable mediumhaving instructions stored thereon, the instructions being executable byone or more processors. The instructions generally include instructionsfor obtaining a FDD-specific feature group indicators (FGIs) set and aTDD-specific FGIs set, and instructions for signaling at least one ofthe FDD-specific FGIs set or TDD-specific FGIs set.

Certain aspects provide a computer-program product for wirelesscommunications with a user equipment capable of communicating infrequency division duplexing (FDD) and time division duplexing (TDD)modes. The computer-program product typically includes acomputer-readable medium having instructions stored thereon, theinstructions being executable by one or more processors. Theinstructions generally include instructions for receiving signaling ofat least one of a FDD-specific feature group indicators (FGIs) set or aTDD-specific FGIs set, and instructions for determining featuressupported by the UE in at least one of a FDD mode or TDD mode, based onthe received signaling.

Certain aspects provide a computer-program product for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Thecomputer-program product typically includes a computer-readable mediumhaving instructions stored thereon, the instructions being executable byone or more processors. The instructions generally include instructionsfor obtaining a FDD-specific feature group indicators (FGIs) set andTDD-specific FGIs set, instructions for signaling the FGIs set for acurrent mode of operation by the UE, and instructions for taking atleast one action designed to reduce likelihood of transitioning to amode of operation that is different from the current mode of operation.

Certain aspects provide a computer-program product for wirelesscommunications by a user equipment capable of communicating in frequencydivision duplexing (FDD) and time division duplexing (TDD) modes. Thecomputer-program product typically includes a computer-readable mediumhaving instructions stored thereon, the instructions being executable byone or more processors. The instructions generally include instructionsfor obtaining a FDD-specific feature group indicators (FGIs) set and aTDD-specific FGIs set, and instructions for sending a request to a basestation to perform detach and re-attach procedures when changing from afirst mode of operation to a second mode of operation, wherein a FGIsset corresponding to the second mode of operation is transmitted to thebase station during the re-attach procedure.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes at least one processor and a memory coupled to the atleast one processor. The at least one processor is configured to obtaina FDD-specific feature group indicators (FGIs) set and a TDD-specificFGIs set, and signal at least one of the FDD-specific FGIs set orTDD-specific FGIs set.

Certain aspects of the present disclosure provide an apparatus forwireless communications with a user equipment capable of communicatingin frequency division duplexing (FDD) and time division duplexing (TDD)modes. The apparatus generally includes at least one processor and amemory coupled to the at least one processor. The at least one processoris configured to receive signaling of at least one of a FDD-specificfeature group indicators (FGIs) set or a TDD-specific FGIs set, anddetermine features supported by the UE in at least one of a FDD mode orTDD mode, based on the received signaling.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes at least one processor and a memory coupled to the atleast one processor. The at least one processor configured to obtain aFDD-specific feature group indicators (FGIs) set and TDD-specific FGIsset, signal the FGIs set for a current mode of operation by the UE, andtake at least one action designed to reduce likelihood of transitioningto a mode of operation that is different from the current mode ofoperation.

Certain aspects of the present disclosure provide an apparatus forwireless communications capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes. The apparatusgenerally includes at least one processor and a memory coupled to the atleast one processor. The at least one processor is configured to obtaina FDD-specific feature group indicators (FGIs) set and a TDD-specificFGIs set, and send a request to a base station to perform detach andre-attach procedures when changing from a first mode of operation to asecond mode of operation, wherein a FGIs set corresponding to the secondmode of operation is transmitted to the base station during there-attach procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 illustrates a multiple access wireless communication system, inaccordance with certain aspects of the present disclosure.

FIG. 2 illustrates a block diagram of a communication system, inaccordance with certain aspects of the present disclosure.

FIG. 3 illustrates an example wireless communication system, inaccordance with certain aspects of the present disclosure.

FIG. 4 illustrates example operations that may be performed by a userequipment (UE), in accordance with certain aspects of the presentdisclosure.

FIG. 5 illustrates example operations that may be performed by anetwork, in accordance with certain aspects of the present disclosure.

FIG. 6 illustrates example operations that may be performed by a UE, inaccordance with certain aspects of the present disclosure.

FIG. 7 illustrates alternative example operations that may be performedby a UE, in accordance with certain aspects of the present disclosure.

DETAILED DESCRIPTION

The techniques described herein can be used for various wirelesscommunication networks such as Code Division Multiple Access (CDMA)networks, Time Division Multiple Access (TDMA) networks, FrequencyDivision Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms“networks” and “systems” are often used interchangeably. A CDMA networkcan implement a radio technology such as Universal Terrestrial RadioAccess (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) andLow Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856standards. A TDMA network can implement a radio technology such asGlobal System for Mobile Communications (GSM). An OFDMA network canimplement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11,IEEE 802.16, IEEE 802.20, Flash-OFDM, etc. UTRA, E-UTRA, and GSM arepart of Universal Mobile Telecommunication System (UMTS). Long TermEvolution (LTE) is an upcoming release of UMTS that uses E-UTRA. UTRA,E-UTRA, GSM, UMTS and LTE are described in documents from anorganization named “3rd Generation Partnership Project” (3GPP). cdma2000is described in documents from an organization named “3rd GenerationPartnership Project 2” (3GPP2). These various radio technologies andstandards are known in the art. For clarity, certain aspects of thetechniques are described below for LTE, and LTE terminology is used inportions of the description below.

Single carrier frequency division multiple access (SC-FDMA), whichutilizes single carrier modulation and frequency domain equalization isa technique that can be utilized with various aspects described herein.SC-FDMA has similar performance and essentially the same overallcomplexity as those of an OFDMA system. SC-FDMA signal has lowerpeak-to-average power ratio (PAPR) because of its inherent singlecarrier structure. SC-FDMA has drawn great attention, especially in theuplink communications where lower PAPR greatly benefits the mobileterminal in terms of transmit power efficiency. It is currently aworking assumption for an uplink multiple access scheme in 3GPP LongTerm Evolution (LTE), or Evolved UTRA.

Referring to FIG. 1, a multiple access wireless communication systemaccording to one aspect is illustrated. An access point 100 (AP)includes multiple antenna groups, one including 104 and 106, anotherincluding 108 and 110, and an additional including 112 and 114. Anaccess point (AP) may also be referred to as a base station (BS),eNodeB, or simply eNB. In FIG. 1, only two antennas are shown for eachantenna group, however, more or fewer antennas can be utilized for eachantenna group. Access terminal 116 (AT) is in communication withantennas 112 and 114, where antennas 112 and 114 transmit information toaccess terminal 116 over forward link 120 and receive information fromaccess terminal 116 over reverse link 118. An access terminal (AT) mayalso be referred to as a user terminal (UT), mobile station (MS), userequipment (UE), wireless communication device, or some otherterminology. Access terminal 122 is in communication with antennas 106and 108, where antennas 106 and 108 transmit information to accessterminal 122 over forward link 126 and receive information from accessterminal 122 over reverse link 124. In a frequency division duplex (FDD)system, communication links 118, 120, 124 and 126 can use differentfrequencies for communication. For example, forward link 120 can use adifferent frequency than that used by the reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point. In oneaspect, respective antenna groups are designed to communicate withaccess terminals in a sector of the areas covered by the access point100.

In communication over forward links 120 and 126, the transmittingantennas of access point 100 may utilize beamforming in order to improvethe signal-to-noise ratio of forward links for the different accessterminals 116 and 122. Also, an access point using beamforming totransmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access point transmitting through a single antenna to all of itsaccess terminals.

FIG. 2 is a block diagram of an aspect of a transmitter system 210(e.g., an access point) and a receiver system 250 (e.g., an accessterminal) in a MIMO system 200. At the transmitter system 210, trafficdata for a number of data streams is provided from a data source 212 toa transmit (TX) data processor 214.

In an aspect, each data stream is transmitted over a respective transmitantenna. TX data processor 214 formats, codes, and interleaves thetraffic data for each data stream based on a particular coding schemeselected for that data stream to provide coded data.

The coded data for each data stream can be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and can be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (e.g., symbol mapped) basedon a particular modulation scheme selected for that data stream toprovide modulation symbols. Examples of modulation schemes may includeBinary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK),M-PSK, or M-QAM (Quadrature Amplitude Modulation) where M is an integer.The data rate, coding, and modulation for each data stream can bedetermined by instructions performed by processor 230, which may becoupled with the memory 232.

The modulation symbols for respective data streams are then provided toa TX MIMO processor 220, which can further process the modulationsymbols (e.g., for OFDM). TX MIMO processor 220 then provides N_(T)modulation symbol streams to N_(T) transmitters (TMTR) 222 a through 222t. In certain aspects, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270, which may be coupled with the memory 272, periodicallydetermines which pre-coding matrix to use. Processor 270 formulates areverse link message comprising a matrix index portion and a rank valueportion. The reverse link message can comprise various types ofinformation regarding the communication link and/or the received datastream. The reverse link message is then processed by a TX dataprocessor 238, which also receives traffic data for a number of datastreams from a data source 236, modulated by a modulator 280,conditioned by transmitters 254 a through 254 r, and transmitted back totransmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

In an aspect, logical channels are classified into Control Channels andTraffic Channels. Logical Control Channels comprise a Broadcast ControlChannel (BCCH), which is a downlink (DL) channel for broadcasting systemcontrol information; a Paging Control Channel (PCCH), which is a DLchannel that transfers paging information; and a Multicast ControlChannel (MCCH), which is a point-to-multipoint DL channel used fortransmitting Multimedia Broadcast and Multicast Service (MBMS)scheduling and control information for one or several MTCHs. Generally,after establishing an RRC (radio resource control) connection thischannel is only used by user equipments (UEs) that receive MBMS (Note:old MCCH+MSCH). Dedicated Control Channel (DCCH) is a point-to-pointbi-directional channel that transmits dedicated control information andused by UEs having an RRC connection. In an aspect, Logical TrafficChannels comprise a Dedicated Traffic Channel (DTCH), which is apoint-to-point bi-directional channel, dedicated to one UE, for thetransfer of user information; and a Multicast Traffic Channel (MTCH),which is a point-to-multipoint DL channel for transmitting traffic data.

In an aspect, Transport Channels are classified into DL and uplink (UL).DL Transport Channels comprise a Broadcast Channel (BCH), DownlinkShared Data Channel (DL-SDCH) and a Paging Channel (PCH), the PCH forsupport of UE power saving (DRX cycle is indicated by the network to theUE), broadcasted over entire cell and mapped to PHY resources which canbe used for other control/traffic channels. The UL Transport Channelscomprise a Random Access Channel (RACH), a Request Channel (REQCH), anUplink Shared Data Channel (UL-SDCH), and a plurality of PHY channels.The PHY channels comprise a set of DL channels and UL channels.

Exemplary Methods and Apparatus for Employing Different Capabilities forDifferent Duplexing Modes

Current 3GPP specifications may define a set of feature group indicators(FGIs), which are signaled by the user equipment (UE) to the network toindicate support or non-support for certain LTE and Inter-Radio AccessTechnology (I-RAT) features. Examples of such features may includesupport for handover, performing measurements on another RAT,semi-persistent scheduling and various other features. An example listof definitions for FGIs that may be signaled by a UE may be found in3GPP 36.331. Based on the signaled FGIs from the UE, the network may notinitiate certain procedures towards the UE, since these may not besupported in the UE.

Currently, feature group indicator (FGIs) in the LTE do not specify themode of operation (e.g., FDD or time division duplex (TDD)) to whichthey apply. Hence, a UE supporting a certain feature set is, perspecification, required to support the full feature set in both FDD andTDD modes of operation. This may be undesired from a product releaseperspective, because certain features may become available in one mode(e.g., FDD) sooner than in the other mode of operation (e.g., TDD).Hence, according to the specifications, a device that is capable ofoperating in both FDD and TDD modes may have to restrict feature supportto only include features that are supported in both of the duplexingmodes of operation.

According to certain aspects of the present disclosure, however,separate groups or sets of capabilities (e.g., feature group indicators(FGIs)) may be defined for different modes of operation (e.g., LTE FDDand LTE TDD). One approach to implement separate groups of FGIs may beto utilize the current set of FGIs (e.g., as defined in the Rel-8 of theLTE standard) (or a slightly modified version thereof) as beingapplicable only for LTE FDD, while a new set of FGIs may be addedspecifically for TDD mode. Alternatively, the current set of FGIs (or aslightly modified version thereof) may be defined as being applicableonly for LTE TDD mode, while a new set of FGIs may be added specificallyfor FDD mode. In this manner, for example, a UE may indicate support forTDD and FDD features independently. As a result, a feature that issupported in only one of the modes (e.g., FDD) can be made availableearlier, even if the feature is not supported in the other mode (e.g.,TDD).

For certain aspects, in order to have separate groups of FGIs fordifferent modes of operation, the entire FGI table (e.g., the tableshowing correspondence of FGIs and features) may be split in twocolumns, one corresponding to the LTE TDD and the other corresponding tothe LTE FDD mode of operation. The last bit of the FGIs (e.g., the mostsignificant bit, bit number 32) may be used to toggle between the twocolumns/modes. This may allow the UE, for example, to send informationin only one of the columns over the air at any time.

Certain aspects may enable a UE provider to reduce time to market fornew handsets (e.g., LTE handsets) that support both FDD and TDD. Theproposed method allows a UE to support a wider range of features in onemode without being constrained by the unavailability of those featuresin the other mode.

FIG. 3 illustrates a block diagram of an example wireless communicationssystem 300 in which the feature support for TDD and FDD may bedecoupled, as presented herein.

System 300 may include one or more UEs (terminals, mobile or wirelessstations, and the like), such as UE 310. The UE 310 may communicate withone or more eNBs 330 (base stations, access points, Node Bs, networkcells, and the like) on an uplink and/or downlink. In an aspect, the UE310 and the eNB 330 can include any number of antennas (not shown) forUL/DL communication within the system 300.

In various wireless communication deployments, respective UEs can beconfigured with different levels of capability and, in some cases, withdifferent features supported in different operating modes. For example,for an LTE system, the UE 310 may be capable of supporting a first setof features in the TDD mode and a second set of features in the FDDmode. To allow the UE 310 to independently signal these different setsof features, the UE 310 may obtain/maintain a FDD-specific FGIs set 316and a TDD-specific FGIs set 318. The UE may decide which set of featuresto signal using a processing module 314. The UE may also include atransmitter module 312 for transmitting the FDD-specific and/orTDD-specific FGIs to the eNB. The receiving module 320 may be used forreceiving downlink communications from the eNB.

At any given time, the UE 310 may signal one or both of themode-specific FGIs to the eNB 330. The eNB 330 may receive the one (orboth) of the mode-specific FGIs with a receiver module 332. The eNB maythen determine what features are supported by the UE in a given mode(e.g., with a feature determination module 334). In some cases, the eNBmay receive only the set of FGIs for a current operating mode, determinewhat features are available, and initiate procedures for the UEaccordingly. According to certain aspects, the eNB may receive signalingof both sets of FGIs and, for example, determine what features areavailable in both and initiate a transition between modes accordingly.The eNB may also use a transmitter module 336 to transmit signals to theUE 310.

FIG. 4 illustrates example operations that may be performed by a userequipment (UE), such as the receiver system 250, as illustrated in FIG.2, in accordance with certain aspects of the present disclosure.

The operations 400 begin, at 402, by obtaining a set of TDD specificfeature group indicators (FGIs) and set of FDD FGIs. In the illustratedexample, if the UE is operating in FDD mode, the UE may signal theFDD-specific FGIs set, at 404. On the other hand, if the UE is operatingin TDD mode, the UE may signal the TDD-specific FGIs set, at 406.According to certain aspects, the UE may signal both the TDD-specificFGIs set and FDD-specific FGIs set, regardless of the current duplexingmode.

For certain aspects, the UE may signal the FDD-specific FGIs set orTDD-specific FGIs set as part of a Capability Update procedure.

FIG. 5 illustrates example operations that may be performed by a networkor an eNB, such as the transmitter system 210, as illustrated in FIG. 2,in accordance with certain aspects of the present disclosure. Theoperations 500 begin, at 502, by receiving signaling of TDD-specificFGIs set and/or FDD-specific FGIs set from a UE. At 504, a determinationof features supported by the UE is made, based on the received FGIs setor sets. At 506, procedures are initiated with the UE, based on thereceived FGIs set or sets and the features that are supported by the UE.

For certain aspects, the UEs may advertize different sets of features inFDD and TDD modes. However, in the current versions of the LTE standard,the UE capability may only be sent by the UE upon attach. Subsequently,the UE capability may be exchanged directly between the eNBs, even ifthe eNBs operate in different modes. This means that the eNBs may notrequest an updated UE capability upon a mode change. Therefore, forcertain aspects, the UE may force a UE capability exchange upon a modechange to make sure that the eNBs have the FGIs set related to the newmode of operation. For certain aspects, the UE may force a UE capabilityexchange (and hence FGIs set exchange) by performing a detach/re-attachprocedure, as further described herein.

Initially, the UE may advertize different sets of FGIs for LTE FDD andLTE TDD modes. The mode of operation may be chosen based on the firsteNB that the UE has camped on during cell selection on LTE (e.g., whenUE tries to find both FDD and TDD systems). Once the mode of operationis chosen, certain aspects of the present disclosure relate to methodsand apparatus for reducing and/or preventing mobility between differentmodes of operation (e.g., LTE FDD to LTE TDD, LTE TDD to LTE FDD, andLTE TDD RAT to UTRAN/1×/HRPD RAT, in which UTRAN stands for UniversalTerrestrial Radio Access Network, 1× refers to the CDMA2000 1×, and HRPDstands for high rate packet data). In accordance with certain aspects,while operating in TDD mode, the UE may prune out neighbor FDDfrequencies (or frequency bands) in a system information block (e.g.,SIB5). The system information block type 5 (SIB5) contains parametersfor the configuration of the common physical channels in the cell.Similarly, while operating in FDD mode, the UE may prune out neighborTDD frequencies in the SIB5.

According to certain aspects, the UE may reduce and/or prevent (e.g.,disable) LTE TDD inter-radio access technology (I-RAT) mobility toUTRAN/1×/HRPD during idle mode by pruning out the correspondingfrequencies in the SIB6 and SIB8. The system information block type 6(SIB6) contains parameters for the configuration of the common andshared physical channels to be used in connected mode. The systeminformation block type 8 (SIB8) contains static common packet channel(CPCH) information to be used in the cell.

Certain aspects of the present disclosure relate to methods andapparatus for reducing and/or preventing LTE FDD to LTE TDD and LTE TDDto LTE FDD mobility while the UE is in the active mode. According tocertain aspects, while the UE is in LTE FDD mode, the UE may reduceand/or prevent active mode mobility by disabling LTE TDD frequency bandsin the UE capability information element (IE). Similarly, while the UEis in LTE TDD mode, the UE may disable LTE FDD frequency bands in the UEcapability IE.

According to certain aspects, while in LTE TDD, the UE may reduce and/orprevent active mode LTE TDD IRAT mobility to UTRAN/1×/HRPD by disablingUTRAN/1×/HRPD frequency bands in the UE capability IE.

In case of a mode change, certain aspects of the present disclosure mayforce the eNB to query for updated UE capability information. If themode change happened as a result of an out of service/radio link failure(OOS/RLF) based mobility, the UE may force detach/re-attach procedures,so that at least one new FGIs set is exchanged. For certain aspects, anew flag may be added to the service indication application programminginterfaces (API) from radio resource control (RRC) connection layer tonon-access stratum (NAS) connection layer, indicating if FDD/TDD mode ofoperation change has happened. The mode change may be indicated by RRCto NAS as soon as the FDD/TDD mode change is detected by the RRC,regardless whether the UE is in idle or connected mode. The RRC may keeptrack of the current FDD/TDD mode and the FDD/TDD mode that waspreviously camped on. If the FDD/TDD mode change is indicated to NAS atservice indication, the NAS may trigger a detach procedure followed by are-attach procedure. NAS may also inform data stream (DS) layer torelease existing bearer contexts.

For certain aspects, unless the network releases the RRC connectionafter detach, the UE may use the same RRC connection for the subsequentattach request as per Release 8/9 specifications of the LTE standard(note that a separate RRC connection may be required in Rel-10 of theLTE standard).

For certain aspects, for the out of service (OOS) based mobility, the UEmay try to search for service starting with the frequencies/frequencybands of the systems with the same mode (e.g., FDD) as the lastsuccessfully camped systems. For example, if the UE last camped on FDD,the UE may begin looking for service on FDD systems. Similarly, if theUE last camped on TDD, the UE may begin looking for service on TDDsystems.

For certain aspects, in the event that a detach procedure is triggered,the internet protocol (IP) connectivity may be lost and may need to bere-established. This may result in degraded end-user experiencedepending on application behavior (e.g., restart of application). Forcertain aspects, LTE FDD to LTE TDD mobility (and vice versa) may belimited to OOS procedures. Other mobility procedures such as handover,redirections and reselections may not be executed.

FIG. 6 illustrates example operations that may be performed by a userequipment (UE), in accordance with certain aspects of the presentdisclosure. The UE may be a receiver unit 250 as illustrated in FIG. 2or the UE 310, as illustrated in FIG. 3.

The operations 600 begin at 602 where the UE may obtain a FDD-specificfeature group indicators (FGIs) set and TDD-specific FGIs set. At 604,the UE may signal the FGIs set for its current mode of operation. At606, the UE may take at least one action designed to reduce thelikelihood of transitioning to a mode of operation that is differentfrom the current mode of operation. The UE may utilize the processingmodule 314 to decide which action is suitable.

In some aspects, taking at least one action designed to reduce thelikelihood of transitioning may comprise, during an idle mode, ignoringneighbor frequencies for a mode different from the current mode ofoperation that is broadcasted in a system information block (SIB). Inanother aspect, taking at least one action may comprise disablingfrequency bands for mode of operation that are different from thecurrent mode of operation advertised in a UE capability message.According to another aspect, taking the action may comprise disablinginter-RAT (radio access technology) mobility by disabling frequencybands for one or more RATs advertised in a UE capability message. Takingthe action may also comprise taking action to force a base station toquery for UE capability. For example, a Non Access Stratum (NAS)connection layer may be notified by a Radio Resource Control (RRC)connection layer of a change from the current mode of operation to adifferent mode of operation. The NAS connection layer may cause the UEto perform detachment and re-attachment procedures.

In yet another aspect, taking the action may comprise taking action toforce a base station to force a detachment and re-attachment procedure,while giving bias to the current mode of operation during there-attachment procedure.

According to certain aspects, the current mode of operation may comprisea TDD mode and taking at least one action to reduce the likelihood oftransitioning to a mode of operation that is different from the currentmode of operation may comprise disabling inter-RAT mobility by ignoringfrequencies broadcast in at least one system information block (SIB).

According to certain aspects, the current mode of operation may comprisea TDD mode and taking at least one action may comprise disablinginter-RAT (radio access technology) mobility during an active mode anddisabling frequency bands for a RAT that is different from a current RATwhile in the current mode of operation, in which the frequency bands maybe advertised in a UE capability message.

It should be noted that the method described herein may be usedtemporarily (e.g., to reduce time to market of new handsets). Once themobility between LTE FDD and TDD is supported, it is expected that LTEFDD and TDD feature sets are also aligned. When the FGIs in both the FDDand TDD are aligned (e.g., each feature is supported in both modes), theUE may only send one set of FGIs that correspond to both FDD and TDDmodes of operation.

FIG. 7 illustrates alternative example operations that may be performedby a UE, in accordance with certain aspects of the present disclosure.The UE may be a receiver unit 250 as illustrated in FIG. 2 or the UE310, as illustrated in FIG. 3.

The operations 700 begin at 702 where the UE may obtain FDD-specificcapabilities and TDD-specific capabilities. For certain aspects, thecapabilities may include TDD-specific FGIs set and FDD-specific FGIsset. At 704, the UE may send a request to a base station to performdetach and re-attach procedures when changing from a first mode ofoperation to a second mode of operation. The capabilities correspondingto the second mode of operation are transmitted to the base stationduring the re-attach procedure. In this manner, the UE may performdetach and re-attach procedures when changing from the first mode ofoperation to the second mode of operation. As an example, the first modeof operation may be FDD and the second mode of operation may be TDD. TheUE may transmit TDD-specific capabilities (e.g., FGIs set) to the basestation during the re-attach procedure.

The various operations corresponding to blocks illustrated in themethods of FIGS. 4-7 described above may be performed by varioushardware and/or software component(s) and/or module(s).

For example, means for obtaining a FDD-specific FGIs set andTDD-specific FGIs set may be performed by a processor or any suitableprocessing component, such as the processing module 314, in FIG. 3.Means for signaling at least one of the FDD-specific FGIs set orTDD-specific FGIs set may be performed by a transmitter, such as thetransmitter module 312. Similarly, means for taking at least one actionmay be performed by a processor or any suitable processing component,such as the processing module 314 as illustrated in FIG. 3. In addition,means for receiving signaling may be performed by a receiver, such asthe receiver module 332, and means for determining features supported bythe UE may be performed by a processing unit, such as the featuredetermination module 334, as illustrated in FIG. 3. Similarly, means forsending a request to a base station to perform detach and re-attachprocedures may be performed by a transmitter, such as the transmittermodule 312.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array signal (FPGA) or other programmable logic device(PLD), discrete gate or transistor logic, discrete hardware componentsor any combination thereof designed to perform the functions describedherein. A general purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thepresent disclosure may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in any form of storage medium that is knownin the art. Some examples of storage media that may be used includerandom access memory (RAM), read only memory (ROM), flash memory, EPROMmemory, EEPROM memory, registers, a hard disk, a removable disk, aCD-ROM and so forth. A software module may comprise a singleinstruction, or many instructions, and may be distributed over severaldifferent code segments, among different programs, and across multiplestorage media. A storage medium may be coupled to a processor such thatthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware or any combination thereof. If implemented in software, thefunctions may be stored as one or more instructions on acomputer-readable medium. A storage media may be any available mediathat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers.

Software or instructions may also be transmitted over a transmissionmedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition oftransmission medium.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

The invention claimed is:
 1. A method for wireless communications by auser equipment (UE) capable of communicating in frequency divisionduplexing (FDD) and time division duplexing (TDD) modes, comprising:obtaining FDD-specific capabilities and TDD-specific capabilities,wherein the FDD-specific capabilities comprise a set of capabilitiessupported in FDD that are not supported in TDD, and wherein theTDD-specific capabilities comprise a set of capabilities supported inTDD that are not supported in FDD; and sending a request to a basestation to perform detach and re-attach procedures when changing from afirst mode of operation to a second mode of operation, wherein theFDD-specific capabilities or the TDD-specific capabilities,corresponding to the second mode of operation, are transmitted to thebase station during the re-attach procedure.
 2. The method of claim 1,further comprising: performing the detach and re-attach procedures whenchanging from the first mode of operation to the second mode ofoperation.
 3. The method of claim 1, wherein the first mode of operationis FDD and the second mode of operation is TDD, wherein the TDD-specificcapabilities are transmitted to the base station during the re-attachprocedure.
 4. The method of claim 1, wherein FDD-specific capabilitiescomprise FDD-specific Feature group indicators (FGIs) set andTDD-specific capabilities comprise TDD-specific FGIs Set.
 5. Anapparatus for wireless communications capable of communicating infrequency division duplexing (FDD) and time division duplexing (TDD)modes, comprising: means for obtaining FDD-specific capabilities andTDD-specific capabilities, wherein the FDD-specific capabilitiescomprise a set of capabilities supported in FDD that are not supportedin TDD, and wherein the TDD-specific capabilities comprise a set ofcapabilities supported in TDD that are not supported in FDD; and meansfor sending a request to a base station to perform detach and re-attachprocedures when changing from a first mode of operation to a second modeof operation, wherein the FDD-specific capabilities or the TDD-specificcapabilities, corresponding to the second mode of operation, aretransmitted to the base station during the re-attach procedure.
 6. Theapparatus of claim 5, further comprising: means for performing thedetach and re-attach procedures when changing from the first mode ofoperation to the second mode of operation.
 7. The apparatus of claim 5,wherein the first mode of operation is FDD and the second mode ofoperation is TDD, wherein the TDD-specific capabilities are transmittedto the base station during the re-attach procedure.
 8. The apparatus ofclaim 5, wherein FDD-specific capabilities comprise FDD-specific Featuregroup indicators (FGIs) set and TDD-specific capabilities compriseTDD-specific FGIs Set.
 9. A non-transitory computer readable mediumhaving instructions stored thereon, the instructions being executable byone or more processors of a user equipment capable of communicating infrequency division duplexing (FDD) and time division duplexing (TDD)modes and the instructions comprising: instructions for obtainingFDD-specific capabilities and TDD-specific capabilities, wherein theFDD-specific capabilities comprise a set of capabilities supported inFDD that are not supported in TDD, and wherein the TDD-specificcapabilities comprise a set of capabilities supported in TDD that arenot supported in FDD; and instructions for sending a request to a basestation to perform detach and re-attach procedures when changing from afirst mode of operation to a second mode of operation, wherein theFDD-specific capabilities or the TDD-specific capabilities,corresponding to the second mode of operation, are transmitted to thebase station during the re-attach procedure.
 10. The computer readablemedium of claim 9, further comprising: instructions for performing thedetach and re-attach procedures when changing from the first mode ofoperation to the second mode of operation.
 11. The computer readablemedium of claim 9, wherein the first mode of operation is FDD and thesecond mode of operation is TDD, wherein the TDD-specific capabilitiesare transmitted to the base station during the re-attach procedure. 12.The computer readable medium of claim 9, wherein FDD-specificcapabilities comprise FDD-specific Feature group indicators (FGIs) setand TDD-specific capabilities comprise TDD-specific FGIs Set.
 13. Anapparatus for wireless communications capable of communicating infrequency division duplexing (FDD) and time division duplexing (TDD)modes, comprising: at least one processor configured to: obtainFDD-specific capabilities and TDD-specific capabilities, wherein theFDD-specific capabilities comprise a set of capabilities supported inFDD that are not supported in TDD, and wherein the TDD-specificcapabilities comprise a set of capabilities supported in TDD that arenot supported in FDD, and send a request to a base station to performdetach and re-attach procedures when changing from a first mode ofoperation to a second mode of operation, wherein the FDD-specificcapabilities or the TDD-specific capabilities, corresponding to thesecond mode of operation, are transmitted to the base station during there-attach procedure; and a memory coupled to the at least one processor.14. The apparatus of claim 13, wherein the at least one processor isfurther configured to: perform the detach and re-attach procedures whenchanging from the first mode of operation to the second mode ofoperation.
 15. The apparatus of claim 13, wherein the first mode ofoperation is FDD and the second mode of operation is TDD, wherein theTDD-specific capabilities are transmitted to the base station during there-attach procedure.
 16. The apparatus of claim 13, wherein FDD-specificcapabilities comprise FDD-specific Feature group indicators (FGIs) setand TDD-specific capabilities comprise TDD-specific FGIs Set.